This invention relates generally to clamping-type brackets which are attachable to shelves or other board-like members to support extension shelves or other objects, and more particularly to a bracket which is installable without tools by means of a removable locking piece.
Clamping-type brackets are adapted to engage a shelf, a desk or table top, or other board-like members, the bracket being formed by an upper arm which rests on the shelf, and a lower arm which lies below the shelf. To secure the bracket to the shelf, the usual practice is to provide a threaded clamping bolt which passes vertically through a bore in the lower arm and terminates in an anchoring disc. By turning the bolt by means of a tool or handle, the disc is forced against the underside of the shelf to secure the bracket in place.
Since the conventional clamping-type bracket is intended for attachment to shelves or other board-like members, the spacing between the upper and lower arms is made sufficiently large to permit use of the bracket with boards in a range of thicknesses. Hence with a thin board, the clamping bolt must be turned almost all of the way in to engage the board, so that only a small section of the bolt projects below the lower arm, whereas with thicker boards the bolt is turned in to a lesser degree and more of it projects below the lower arm.
Apart from the fact that such clamping bolts are unsightly and therefore objectionable in those situations where the bolts are visible, the existing clamping arrangement has a number of other practical drawbacks. Since the bracket is anchored by means of a disk pressed by the bolt into the underside of the shelf or board, this disc tends to cut into the board and mar the finish thereof. Also, unless the disc is very tightly pressed into the board--and this requires a fair degree of strength--it acts as a pivot point, making it possible to swing the bracket thereabout. Such displacement of the bracket is undesirable.